Systems for controlling compression ignition engines

ABSTRACT

In a combined hydraulic and mechanical system for controlling compression ignition engines, a piston means which has a central axis is provided at its exterior with a control surface inclined with respect to this axis. A cylinder means houses the piston means to form a servocontrol therewith, and a wall of the cylinder means is formed with an overflow bore to be covered and uncovered by the piston means. A manually operable speed control means is connected by a linkage means to the piston means while freeing the latter for rotary movement about its axis. A slide valve means communicates with opposed sides of the piston means in the cylinder means to control the flow of fluid pressure thereto, and a governor means which is also connected to the linkage means is operatively connected with the slide valve means to control the latter. The linkage means is also connected with a metering means which meters the amount of fuel delivered to the engine.

United. States Patent Antonin Bulvas Miniee Kra'lup, Czechoslovakia July 1, 1968 Feh. 23, 1971 CKD Praha oborovy podnik Prague, Czechoslovakia July l, 1967, Oct. 31, 1967, June 5, 1968 Czechoslovakia 4853/67, 7690/67 and 4167/68 Inventor Appl. No. Filed Patented Assignee Priority References Cited UNITED STATES PATENTS l/l953 Fiser 3,067,581 12/1962 Reggio ABSTRACT: In a combined hydraulic and mechanical system for controlling compression ignition engines, a piston means which has a central axis is provided at its exterior with a control surface inclined with respect to this axis. Al cylinder means houses the piston means to form a servocontrol therewith, and a wall of the cylinder means is formed with an overflow bore to be covered and uncovered by the piston means. A manually operable speed control means is connected by a linkage means to the piston means while freeing the latter for rotary movement about its axis. A slide valve means communicates with opposed sides of the piston means in the cylinder means to control the flow of fluid pressure thereto, and a governor means which is also connected to the linkage means is operatively connected with the slide valve means to control the latter. The linkage means is also connected with a metering means which meters the amount of fuel delivered to the engine.

- PATENYEU F5523 :an

SHEET 1 UF 8 w L 4 mi L56 q +5. 7.- -l a 3J l l -l ,y a Mv ,2- w NH, .uw/Nw@ 4 3 E 09N/ INVENTOR PATENTED FEB23191| snm a nF a BACKGROUND OF THE INVENTION servopiston The invention relates to a mechanical-hydraulic speed and load governor, more particularly for compression ignition engines, wherein the centrifugal forces of governor weights and the force of a load spring actuate a hydraulic control of a servopiston'that controls the metering of fuel injected by an injection pump in dependence both on the engine speed and the engine load.

According to prior art, for the control of compression ignition engines two kinds of governors are used, a double-stage speed governor or a wide speed range governor. The doublestage speed governor is especially used on engines of traction vehicles, e.g. diesel electric locomotives, wherein the compression ignition engine is connected with a generator which is a power source for the traction motors of the locomotive. The double-stage speed governor comprises two springs to control the centrifugal governor weights, one of them for regulating the idling speed and the other for controlling the rated speed. Within the range from the idling speed to the rated speed, the governor action is automatically eliminated, and theA fuel delivery from the injection pump tothe engine in dependence on the engine loadI is regulated byan auxiliary device that directly acts on the injection pump. l

With diesel electric locomotives there is used, to achieve a change of excitation intensity of an electric generator, a particular power-actuated exciter driven by pressure oil fed by a particular distribution slide valve in dependence on the speed of the governor and on the torque of the engine. This distribution slide valve constitutes an additional part of the governor which increases the latters dimensions.

A disadvantage of the double-stage speed governor resides in its restricted metering of fuel, with the aid of a servopiston, from zero delivery to an amount required for the idling speed of the engine. As soon as the engine idling speed has been attained, the power piston stops moving and a further increase of the fuel amount is effected by the operator through the medium of an auxiliary device irrespective of the governor position. To each fuel charge set in this manner by the operator correspond certain r.p.m. in dependence on the engine load. In the case of a sudden engine relief, the double-stage speed governor can reduce the fuel amount only by a fuel charge to correspond to the engine idling speed. If such reduced fuel amount is insufficient with respect to the relieving ofthe engine, its speed will rise up to the permissible maximum and the operator has to diminish the fuel amount to the necessary value by the auxiliary device. Should the operator fail to intervene in due time, an adverse condition in the running of the engine could take place. To avoid this there are provided on such engines so-called safety governors to prevent destruction of the engine. Such a safety governor, however, complicates the control equipment of the engine.

Marine engines require both kinds of regulation and this is why they are equipped with a wide speed range governor and a special auxiliary device. A wide speed range governor maintains a constant engine speed irrespective of the engine load. The special auxiliary device is actuated manually and directly controls the injection pump so that it maintains a constant injection fuel charge irrespective of the engine speed.

Since the action of the wide speed range governor and of the auxiliary device are antagonistic each of the actions is separated so that either one kind of fuel control is eliminated or the output member of the servopiston is connected to the injection pump by a resilient member. Deformation of the resilient member eliminates simultaneous action of the wide speed range governor and the auxiliary device on the injection pump. Thus, the fuel charge predetermined by the auxiliary device remains constant because any influence of the wide speed range governor is prevented from increasing the fuel amount, due to a deformation of said resilient member. The action of the wide speed range governor toward a reduction of the fuel amount is in no way restricted, so that the wide speed range governor diminishes the fuel amount set by the auxiliary device only within a certain period of time, which is necessary to eliminate the deformation of the intermediate resilient member. This retardation in time is undesirable from the point of view of regulation.

SUMMARY OF THE INVENTION It is thus a primary object of the present invention to provide a control system which will avoid the above indicated drawbacks.

More particularly, it is an object of the invention to provide a system of mechanical and hydraulic controls, which will precisely regulate the supply of fuel to an engine so as to bring about the desired operating characteristics thereof under load.

Another object of the invention is to provide a construction capable of regulating not only the speed of operation of the engine but also the supply of fuel thereto.

Further, it is an object of the invention to provide a construction which is adapted for use with vehicles such as locomotives or with marine propelling engines.

In connection with locomotives, it is a particular object of the invention to provide a structure capable of controlling for a diesel-operated locomotive the manner in which the field current of a generator is regulated.

Disadvantages of the known engine governors are overcome by the mechanical-hydraulic governor according to the present invention, wherein the servopiston means is provided at least with one control surface inclined to axial movement, which cooperates with a fuel outlet port in a wall of a cylinder means of the servocontrol, the servopiston or its piston rod being rotatably connected to a control mechanism of the injection pump, e.g., with the aid of a rotatable head and a linkage and a speed lever.

On the cylindrical exterior of the piston means there are preferably provided four inclined control surfaces having the shape of projections, which divide the circumference of the servopiston into four chambers, two opposed charging chambers and two fuel discharge chambers. The charging chambers are constantly interconnected through overflow ports and permanently interconnected with the cylinder space above the power piston, and the fuel outlet chambers are permanently interconnected through outlet ports with an outlet conduit. In the wall of the cylinder of the servopiston there are provided, substantially at an equal height, four bores of which two opposite charging bores open into the charging chambers and two opposite bores or overflow ports open into the outlet or discharge chambers.

With the mechanical-hydraulic governor adapted to be used in diesel locomotives, the charging chambers formed by oblique control edges within a rotatable cylinder of the servopiston are permanently interconnected through the charging bore with a space in the rotatably cylinder beneath the servopiston and the outlet chambers are permanently connected with the outlet bore. Parts of the controllable bores are interconnected through a channel with one side and the other parts of the controllable bores are interconnected through channels with the other side of an excitation servomotor of the electric generator.

Another advantage of the invention resides in an adaptation to the propulsion of ships or road vehicles. In a transmission gear between a speed control lever and a servopiston there is provided a control member, e.g. a cam, which is mounted on a shaft actuated by the speed lever, wherein the functional part of the cam is formed so that certain fuel charges, set according to a predetermined program, correspond to certain predetermined r.p.m.

BRIEF DESCRIPTION OF DRAWINGS Several embodiments of the invention are shown, by way of example, in the accompanying drawings, wherein:

FIG. 1 is a vertical section through a control system having a single inclined control surface on the servopiston FIG. 2 is a vertical section of another embodiment;

FIG. 3 is a transverse section through the governor along line III-III in FIG. 2;

FIG. 4 is a view of the developed exterior of the servopiston according to FIG. 2;

FIG. 5 is a vertical section through the system as adapted to operation in electric locomotives;

FIGS. 6, 7, 8 show views of the developed servopiston in three different positions;

FIG. 9 shows characteristics of an electric generator and a compression ignition engine;

FIG. I is a longitudinal section through a portion of another embodiment;

FIG. l1 shows characteristics of the predetermined course of governing;

FIG. 12 shows characteristics of governing a steady engine output within a certain speed range.

DESCRIPTION OF PREFERRED EMBODIMENTS The mechanical part of the governor consists substantially of swingingly mounted governor weights 1 which are loaded by a common spring 2 and symmetrically arranged with respect to a vertical axis of rotation.

The hydraulic part of the governor comprises a cylindrical control slide valve 3 slidably mounted in a distribution chamber 4. During governor rotation the control slide valve 3 is actuated by the centrifugal force of the governor weights I, connected thereto in such a manner that the control slide valve 3 is moved up and down. Moreover, the housing also comprises a vertically arranged cylinder means 5 wherein a power piston means 6 is mounted and is adapted to rectilinearly move and also to rotate. The servopiston 6 is of the differential type and defines with its actuating face at the bottom an annular space within the cylinder 5, and with its larger actuating face at the top a cylindrical space. The servopiston 6 is provided, on its cylindrical exterior of larger diameter, with a control surface or edge 7 which is inclined or oblique with respect to the rectilinear piston movement within the cylinder 5. The distribution chamber 4 communicates intermittently through an overpressure duct 8, with the aid of the control slide valve 3 with the cylindrical space of the cylinder 5 above the servopiston 6 and through a pressure duct 9 with the annular space beneath the servopiston. In the wall of the cylinder 5 an overflow bore 1l is provided, with which cooperates the control edge 7 of the piston 6 during its rectilinear motion. A wall of the distribution chamber 4 is provided with an inlet 12 and an outlet 13'for pressure oil The servopiston 6 has a plunger 14 whose cylinder communicates through a balancing channel 15 with a cylinder of a compensating piston 16, the latter being preloaded from both sides with identical balance springs 17. The cylinder of the compensating piston 16 communicates through a channel 15' with the distribution chamber 4 and also with an outlet which is manually controlled by a needle valve 18. The servopiston 6 has a piston rod 19 which is provided with a fuel control lever 20 having the shape of a perpendicular arm. On the piston 19 is a head 21 rotatably mounted, which is articulated to a speed control 28 through a linkage means 22 to 27, and also to a shaft 34, which actuates a control rack of an injection pump to form a metering means. The linkage consists of a pull rod 22 that is connected to a two-arm lever 23 rotatably mounted on a pin 24 which is connected at its other end to a rod 25. The rod 25 is articulated to a two-armed lever 26 whose other arm is connected, through a pull rod 27, to the speed lever 28 mounted on a pin 30 to rotate thereon. To the pull rod 29 a base 3l of the load spring 2 is articulated. To the pull rod 22 is attached through a pin 32 an end of a swinging lever 33 that is keyed on the shaft 34.

The operation of the above described system is as follows:

With the engine at rest, the governor weights 1 assume a position indicated by line l nearest to the axis of rotation. The control slide valve 3 assumes its lowermost position, and the overpressure duct 8 and the pressure duct 9 are simultaneously open. The speed lever 28 and the servopiston 6 are in their upper position, i.e. the stop" position marked by a dashed line. The oil pressure in the inlet 12 is zero because the oil pump (not shown) is at rest, too. A joint 25' between the rod 25 and the two-arm lever 26 is temporarily fixed. Prior to starting the engine, the speed lever 28 is set in a vertical plane to a position of starting r.p.m., whereby the force of the load.l spring 2 is somewhat increased by its depression. The fuel lever 20 is partly rotated in a horizontal plane to a position corresponding to a starting fuel charge. This starting fuel charge is defined by the height Y of the control edge 7 above the overflow bore 11. In putting the oil pump into action, the pressure oil is forced through the inlet l2 via the overpressure duct 8 out of the distribution chamber 4 into the cylinder 5 above the servopiston 6 and simultaneously via the pressure duct 9 beneath the servopiston 6, i.e. into the annular space with the smaller effective or active area. The servopiston 6 assumes, due to oil overpressure action on its larger effective or active area, a position that corresponds to the fuel charge as set by the fuel lever 20, that is, the servopiston is displaced only within the height Y.

To each height position of the servo cylinder 6 and, consequently, to each height Y set by the rotation of the servopiston with the control edge 7 corresponds a different fuel amount to be delivered by the injection pump to the engine. By uncovering the overflow bore 11 by means of the control edge 7 of the servopiston, piston, the movement of the servopiston 6 into the fuel, as induced by the governor weights, is cut off because the pressure oil regulated by the control slide valve 3 and fed through the overpressure duct 8 to the upper face of the servopiston 6 commences to escape through the overflow bore 11. The height Y andthe resultant movement of the power piston 6 with the control edge 7 can be changed at will by rotating the servopiston 6 by the fuel lever 20, thus controlling the output of the engine. If the height Y equals the total stroke of the servopiston 6, then the overflow bore will not be opened. Instead, it remains covered by its cylindrical portion. The servopiston can perform a full stroke. If the height is zero, i.e. with the overflow bore l1 uncovered by the control edge 7 at the instant the servopiston 6 assumes its position for a zero fuel delivery, the servopiston 6 is not responsive to eventual pulses from the governor weights 1 and the engine cannot be started or, if it is running, it will be stopped by the governor.

With the engine once started, the operating r.p.m. equaling, for example, 50 percent rated engine speed will be set by the speed lever 28. This position of speed lever 28 is shown in FIG. l. At the same time, the speed lever 20 assumes its extreme position wherein the system can set maximum fuel delivery in accordance with instantaneous engine load. As soon as the engine reaches the speed set by the speed lever 28, the forces of the governor weights 1 and the force of the load spring 2 are balanced. The control slide valve 3 simultaneously assumes its intermediate neutral position, thus keeping the overpressure duct 8 covered.

If the preset fuel charge is too small for a given load, the engine speed drops due to insufficient fuel delivery, so that the balance between the force of the governor weights and that of the load spring is disturbed. The governor weights assume a position indicated by line l, and the control slide valve 3 uncovers the overpressure duct 8. The pressure oil forces the servopiston 6 into the fuel and increases the fuel charge. With the increased fuel delivery, the engine speed rises and the governor weights are displacing themselves to position III whereby the control slide valve 3 is moved from its neutral position and interconnects the overpressure duct 8 with the outlet 13. The pressure oil over the servopiston 6 escapes to the outlet and the oil within the pressure duct 9 displaces the servopiston 6 in an upward direction, thus reducing the fuel charge.

With the power piston 6 moving, there is also displaced the plunger 14 which operates the compensating device, i.e. the compensating piston 16 together with the springs l7. The movement of plunger 14 causes both a volumetric and pressure change within the compensating device, which temporarily acts on the control slide valve 3 and returns the same to its intermediate neutral position, whereby the overpressure duct 8 is covered and the movement of the servopiston 6 cut off. The activity of the hydraulic compensating device can be set by the needle valve 18.

To stop the engine the speed lever 28 is set to position stop," or the servopiston 6 can be set by rotating the fuel lever 20 to zero fuel delivery.

The simple servopiston with one oblique control edge 7, as described, has a disadvantage in that the servopiston 6 is loaded by oil pressure on one side of its cylinder. This inconvenience is overcome by an adaptation of the servopiston 6 and its cylinder 5 as shown in FIGS. 2, 3 and 4. On the larger diameter portion of the cylindrical exterior of the servopiston 6 there are provided, on the circumference, four oblique control edges 7 having the shape of helixlike projections. These projections divide the circumference of the servopiston 6 into four equal chambers, two opposite charging chambers 35 and two opposite outlet chambers 36. The charging chambers 35 are constantly interconnected through'overflow ports 37 provided in the servopiston 6 in a direction of its longitudinal axis with the space of the cylinder 5 above the servopiston 6. The outlet chambers 36 are constantly interconnected, through the outlet ports 38 in the servopiston jacket, with the outlet. In a wall of the servopiston cylinder V5 there are arranged, at the same height, four radial bores, wherefrom two opposite charging bores 39 open into the charging chambers 35 and two opposite bores or overflow bores l1 open into the outlet chambers 36. i

The operation and function of the servopiston 6 having four control edges 7 is substantially the same as that ofthe servopiston witha singlecontrol edge .7, shown in FIG. 1. Pressure oil is interruptedly fed through the pressure duct 9 into the annular space 5' of the cylinder 5. At the same time pressure oil is fed through the overpressure duct 8, when it is uncovered by the control slide valve 3, through the charging bores 39 into the charging chambers 35 of the servopiston, and through the overflow ports 37 into the cylinder 5 above the servopiston 6. With an axial movement of the servopiston 6, caused by the centrifugal weights of the governor, the charging bores 39 relatively move in a plane A-A (FIG. 4) and can perform a full stroke since the plane A-A passes only through the charging chamber 35. lnterconnecting the charging bore 39 with the outlet chamber 36 is not obtained on its full relative movement in the plane A-A. Upon rotating the servopiston 6 through the fuel lever 20 so that the charging bore 39 relatively moves under an axial movement of the servopiston in a plane B-B, the charging bore 39 passes over the control edge 7. At the same time the charging bore 39 is only partially covered by the control edge 7 and partially opened into the outlet chamber 36. Pressure oil flows from the control slide valve 3 through the outlet port 38 to the outlet. The control edge 7 simultaneously partly covers the overflow bore 11 and partly uncovers this overflow bore into the charging chamber 35. The oil in the space above the servopiston 6 escapes through the overflow port 37, the charging chamber 35, and the overflow bore 1l into the outlet until balance of the pressures on both sides of the servopiston 6 which stops halfway into the fuel is achieved, thus restricting both the amount of fuel and output of the engine. If the servopiston 6 is further rotated until the charging bore 35 reaches the plane C-C, the charging bore 39 will be interconnected through the outlet port 39 into the outlet with the servopiston in its upper position and set to zero fuel delivery. The system stops the engine, if running, or prevents its starting if it has been at rest.

If the plane of the relative movement of the charging bore with the servopiston 6 rotated is arbitrarily situated between extreme planes A-A and CC, then this plane passes through the charging chamber 35 and the outlet chamber 36. In the zone of relative movement of the charging bore 39, when passing through the charging chamber 35, the wide speed range control up to the margin of limitation is retained, which is given by the covering of the charging bore 39 by the control edge 7 and by stopping of the servopiston at its downward movement into the fuel. In the zone of the relative movement of the charging bore 39, passing through the outlet chamber 36, the wide speed range character of the control is eliminated and the servopiston returns, due to action of the pressure difference, downwards to the lowering of fuel charge and stops again in the position with the control edge 7 covering the charging bore 39.

The system controls the engine as a wide speed range system until the servopiston reaches the position of preset load through the fuel lever 20, i.e. a position, wherein the control edge 7 is set to the height Y from the overflow bore ll. The system maintains the engine speed up to this preset extreme position preset by the speed lever 28, at a constant value irrespective of load. When exceeding the extreme position, the engine speed will drop, because the system cannot exceed the set fuel amount. A changeover to double-stage speed vcontrol can be effected at any position of the system at will of the operator, in that by turning of the fuel lever 20 the servopiston 6 is set to the required fuel amount and the speed lever 28 will Y be set to the maximum permissible enginespeed. Due to overbalance of the load spring 2, the control slide valve 3 leaves the overpressure duct 8 leading to the space above the servopiston 6, which can only assume a position that corresponds with appropriate setting of the fuel lever 20. Thus the amount of fuel is maintained at a constant value irrespective of the permanently open control of the control slide valve 3. The engine speed will correspond with the set amount of fuel and load. If the amount of fuel as set by the fuel lever 20 is too high for the given load, the engine speed will rise due to excess of fuel. When reaching the limit of permissible engine speed, the control slide valve 3 first covers the overpressure duct 8 and upon exceeding the limit, the control slide valve 3 uncovers the overpressure duct 8 into the waste outlet, through which pressure oil escapes from the space above the servopiston 6. Due to difference of pressures above and beneath the servopiston 6, the servopiston rises, i.e. to the stop positiony and reduces the excess of fuel. The engine speed drops and upon reaching the limit of permissible r.p.m., the control slide valve 3 covers the overpressure duct 8. If the amount of fuel as set by the fuel lever 20 is too low for a given load and the engine speed will drop, then the operator increases the amount of fuel by turning the fuel lever 20.

The design of the mechanical-hydraulic system can be varied in details e.g. ,instead of the rotatable servopiston a rotatable cylinder 5', fitted with a hand lever 20 (FIG. 5) can be provided. Such layout can preferably be employed in governors of diesel-electric locomotives, whereinthe diesel engine is coupled with a generator, constituting a power source for traction motors. The scope of such a system is to control operation of the diesel-electric locomotive on a track having variable inclinations, i.e. to control the loading of the diesel engine in varying safely its overloading even in cases when the engine gives no full output, e.g. due to faulty function of one of the engine cylinders.

Within the rotatable cylinder 5' there is slidably mounted a differential servopiston 6, on whose cylindrical surface four oblique control edges 7 at equal distances are distributed. These control edges 7 define within the space of the rotatable cylinder 5 four identical chambers. Two opposite charging chambers 35 are constantly interconnected with the space of the rotatable cylinder 5' beneath the servopiston 6 through overflow ports 37. Further, two opposite chambers 36 are outlet chambers and are interconnected with outlet bores 40.

In a wall of the rotatable cylinder 5' there are provided four radial bores, at equal ldistances and heights, two of which, opposite charging bores 39, open into the charging chambers 35 and two opposite bores, i.e. overflow bores l1, open into the outlet chambers 36. With the charging bores 39 and the overflow bores 1l cooperate the oblique control edges 7 of the servopiston so that they regulate, i.e. vary their passage area.

The charging bores 39 are interconnected through a channel 42 with one side of a servopiston 43 and the overflow bores 11 are interconnected through another channel 42' with the other side of the servomotor 43. The servomotor 43 consists of a rigid cylinder, which comprises a rotary piston 44 having the form of a wing, or vane, connected through a rod 45 with sliding contact 46 of rotary rheostat 47. The rotary rheostat 47 is connected into a eld winding (not shown) of a diesel-electric locomotive generator.

Preloading of the load spring 2 can be varied with the aid of the speed lever 28 mounted on the pin 30, to rotate thereon. The speed lever 28 is interconnected with the servopiston 6 through a transmission gear that transmits angular motion of speed lever 28 into rotary motion of servopiston 6. The transmission gear comprises a level gear 48, mounted on the piston rod 19 by means of a parallel key, so that it is adapted to freely move axially and to rotate together with the bevel gear 48. Another bevel gear 49, keyed on shaft 50 running in bearings 51, engages with the bevel gear 48. To the shaft 50 an arm 52 is attached, a swinging end of which is connected through a pull rod 53 to the speed lever 28. This connection is constituted by a joint 56 that is mounted to displace in a direction of the longitudial axis of speed lever 28. A swing out of the speed lever 28 is transmitted on to the load spring 2 of the governor weights through the medium of a gearwheel 57, a gear sector 57' and levers 58, 59, which are mounted on a common pin 60 to rotate thereon. To the lever 59 a link 61 is attached, the other end of which is connected to the base 31 of the load spring 2.

ln a steady operational state, as shown in FIG. 6, the overflow bores 1l and the charging bores 39 are covered by control edges 7 of servopiston 6, so that the servomotor 43 is at rest. In this operational condition that equals 50 percent engine loading, the generator output is in equilibrium with the engine output, whose speed has been predetermined manually by means of the speed lever 28 (FIG. 5); with this speed there also is a certain constant fuel charge. lf the rolling resistance of the locomotive is invariable, the locomotive moves at a steady speed. FIG. 9 shows this condition in an equilibrium point 8, which lies on the intersection point of curve I of the generator and curve III of the diesel engine. With this point B also corresponds a certain position B' (FIG. 7) of piston 44 of servomotor 43, wherein the rotary rheostat 47 is set at the minimum resistance value. The diesel engine output is in equilibrium with the generator output.

Should there be, for example, an increase in the rolling resistances of the locomotive, torque of the traction motors will be raised on account of the speed of the locomotive. The equilibrium point B according to FIG. 9 displaces on the generator side along the curve I of generator, towards the point Bl and on the diesel engine side along the curve III towards the point B2. The engine load rises and the predetermined fuel charge is insufficient, so that the engine speed is dropping. The governor weights l shift the control slide valve 3 downwards and this, in turn, opens pressure oil admission, the oil now flowing through the overflow bore 1l into the space of the rotatable cylinder 5' above the servopiston 6. The serovpiston 6 is displaced within a certain distance h (FIG. 7) downwards, i.e. into the position of an increased fuel charge. The pressure oil flows from the space beneath the servopiston 6 through overflow ports 37 into charging chambers 35 and continues flowing through charging bore 39 and through the common channel 42 to the right-hand side of the servomotor 43. Thus the piston 44 is put into action and the sliding contact 46 engages on the rheostat 47 higher resistance values in the field circuit of the generator. The piston 44 simultaneously forces oil through channel 42' to the overflow bores ll and through outlet chamber 36 into the outlet bore 40. Due to drop of generator output the diesel engine is relieved and its speed commences to rise until the governor weights 1 shift the control slide valve 3 upwards thus interconnecting the overpressure duct 8 with the outlet 13. The pressure oil flows out of the space within the rotatable cylinder 5 above the servopiston 6. Consequently, the servopiston 6 returns within the distance h" and decreases the fuel charge until the control edges 7 recover the overflow bores 1l and the charging bores 39. Thus the movement of the servomotor 43 is cut off and the load correction is accomplished. At this retum movement of the servopiston 6 it is simultaneously balanced out the r.p.m. control deviation, thus restoring an equilibrium between load spring 2 and governor weights l. This equilibrium once reached, the control slide valve 3 covers the overpressure duct 8 and movement of the servopiston 6 is cut off. The diesel engine continues running at the same output and the same r.p.m. as before, but at a lower voltage and higher current of the generator, in conformity with the new equilibrium state at the point B2 of curve Ill (FIG. 9).

Due to weakening of the generator magnetic field through servomotor 43, the position of the equilibrium point B of curves I, III (FIG. 9) varies and is displaced along the motor curve III to new generator curve, lying between curves l and Il and intersecting curve III in point B2. The point B2 illustrates the new equilibrium state with the regulation accomplished. With the rolling resistances rising, the point B, moving on curve III, can coincide with the point A. In this position, the distance between curves I and III is at its maximum and the servomotor 43 also determines weak resistance values that correspond with the position A' of piston 44 of servomotor 43 (FIG. 6). If the point B displaces along a zone of curve III (FIG. 9) from point A to point D, the piston 44 of servomotor 43 (FIG. 6) also moves from point A to point D and engages lower resistance values on the rotary rheostat 47 in cornpliance with decreasing distance between curves I and III of the range in question (FIG. 9).

As soon as the point D of the intersection point of curves l and III is reached, new equilibrium between the diesel engine output and the generator output at minimum electric resistance in its field winding is obtained. If any of the engine cylinders fails to correctly operate, the engine output drops and the equilibrium between output and loading is disturbed. The r.p.m. of the engine drops, and the device according to the invention relieves the engine load in the manner described.

Operation of the system when the rolling resistances are relieved is similar to that described. The loading correction once accomplished, the engine operates again at the same speed and the same output as before, however, with a higher voltage and a lower current.

The controlling procedure as described is the same for every degree of engine speed, or condition, determined by various compression of the load spring 2 by the speed lever 28.

When starting the locomotive to move, it is necessary to use maximum torque of the engine to overcome the resistances. This can be achieved so that the rotatable cylinder 5' is partly rotated through the medium of the manual fuel lever 20 towards increasing of the fuel charge, until the overflow bores 11 (FIG. 8) reach a plane C-C. In uncovering the overflow bores 11 and charging bores 39, the servomotor 43 is put into action and sets the minimum resistance values on the rotary rheostat 47. The system is thus able to set its maximum amount by sifting the servopiston 6 towards increasing the fuel charge. To ensure economical operation of the engine it is necessary to put the locomotive into motion to return the fuel lever 20 to its initial position.

For marine or road vehicle engines the embodiment as shown in FIG. 10 is advantageous. Into the transmission gear, which transmits swinging motion of the speed lever 28 into rotary motion of the servopiston 6, a control member e.g. a cam 68, is inserted. The cam 68 is mounted on a shaft together with a gearwheel 70, which engages with the gearwheel 57, keyed on the pin 30 together with the speed lever 28. The functional portion of the cam is constituted so that to certain predetermined r.p.m., certain fuel charges are associated, preset in accordance with a predetermined program. A roller 66, disposed on one leg of a bellcrank 64, is forced to the cam by a coil spring 67. The bellcrank 64is mounted on a pin 65 to rotate thereon and to its other leg a pull rod 53, connected vwith its other end to arm 52, is attached. The remaining portion of the transmission gear is identical with that of FIG. 5.

Diagrams in FIGS. 11 and l2 show an output range of the engine governed in'avccordance with the invention, wherein r.p.m. n of the engine are plotted in percents in a vertical axis and engine load P, -in percents, too, is plotted on the horizontal axis. In FIG. 1l the output range is restricted by a preliminary determined characteristic consisting of two parts: part L of resistance curve of a ship propeller with adjustable blades in their maximum position; in the zone between 50 to 70 percent rated engine r.p.m., on the oney hand, and part K of constant engine chargingline inthe range between 75 percent to l() percent rated engine r.p.m. The characteristic according to FIG. 3 comprises two parts, as well: part K of constant engine charging line between 5.01075 percent rated engine r.p.m., on the one hand, and part V of constant engine output in the range between 75 percent to 100 percent rated engine r.p.m.

With the speed lever 28 moving, thepreload of the load spring 2 varies and, consequently, the engine speed, too. Simultaneously is rotated, through the gearwheels 57, 70', the cam 68, swinging out the lever 64. Its swing out is transmitted through the pull rod 53, the arm 5,2,the shaft 50 and the bevel gears 49, 48 to the servopiston 6. As long as the roller 66 rolls on the base circle of the cam 68, the servopiston 6 remains inoperative. The control edges 7 of the servopiston 6 have a permanent adjustment to enable full stroke ofthe servopiston 6.

The cam according to version A,.will restrict the engine output at high r.p.m., i.e., for example, in the range 4above 75 ),percent rated engine speed. In the' range below 75 percent rated engine speed (FIG. 3) the system will meter the fuel according to the line of the constant charging up to 75 percent rated engine speed. When an engine speed'above 75 percent rated engine r.p.m. is set by means of the speed lever 28, the cam 68 strikes on the roller 66, which deviates and this movement makes itself apparent by a rotation of the servopiston 6, which restricts the fuel amount and, consequently, engine output, too. The course of this restriction is given by the shape of the cam 68, which can, for example, be chosen so that according to a known previous consumption of fuel, a constant engine output within the predetermined range of speed (FIG.

l2) can be retained. This tion motors.

With the cam 68 in version B,"v the engine output is limited program is also applicable to tracwithin the range of r.p.m. below 75 percent of nominal engine v speed (FIG. 1l). The cam 68 can be shaped so that the fuel metering for the engine is conformed to the output required. Such a solution is particularly suitable for marine engines having propellers with adjustable blades.

When rotating the cam by actuating the speed lever 2,8, and by rotating the servopiston it is possible to control the fuel amount in accordance with a predetermined speed program, i.e. to meter a certain fuel charge t0- certain predetermined r.p.m. An opposite solution is possible, too, wherein certain fuel charges are associated to certain r.p.m. The cam is then actuated by a movement of the servopiston actuating the speed lever by its movement.

l claim:

1. In a system for controlling compression ignition engines, piston means having a central axis and an exterior control surface inclined with respect to said axis, cylinder means housing said piston means and guiding the latter for movement along said axis thereof, said cylinder means forming a servocontrol with said piston means and said cylinder means being formed with an overflow bore extending through a wall of said cylinder means to be covered and uncovered by said piston means, said piston means being rotatable within said cylinder means as well as being axially movable therein, a manually operable speed control means, slide valve means communicating with said cylinder means for controlling the flow of pressure fluid into said 'cylinder means at opposite sides .of said piston means, centrifugal governor means coactmg with said slide valve means for controlling the latter, linkage means coacting with said speed control means, governor means, and piston means for controlling said governor means and said piston means in response to actuation of said speed control means while freeing said piston means for rotary movement about its axis, and metering means operatively connected with said linkage means for metering the supply of fuel to the engine according to the axial position of said piston means in said cylinder means.

2. The combination of claim l'and wherein said piston means has circumferentially distributed about its axis four inclined control surfaces in the form of projections defining at the exterior of said piston means four chambers distributed circumferentially thereabout and forming one pair of opposed charging chambers and another pair of opposed discharge chambers, said piston means being formed with one pair of passages providing communication 'between said charging chambers and one side of said piston means and with a second pair of passages providing communication between said discharge chambers and the other side of said piston means, and said cylinder means being formed in a plane perpendicular to said piston axis with a pair of opposed charging bores communicating with chambers said charging chambers and with a pair of opposed overflow bores communicating with said discharge chambers.

3. The combination of claim 2 and wherein said piston means is a differential piston means having at its opposite sides different effective areas the smaller of which is in constant communication with a distribution chamber of said slide valve means and the larger of which is placed in intermittent communication with said distribution chamber by the control of said slide valve means through said centrifugal governor means.

v 4. The combination of claim 3 and wherein a fuel control means is operatively connected to said piston means for regulating the angular position thereof in said cylinder means.

5. The combination of claim l and wherein a cam means is situated between said speed control means and linkage means for controlling said linkage means according to a predetermined prograrn to provide predetermined fuel supplies at certain engine speed ranges.

6. The combination of claim 5 and wherein said linkage means includes a bellcrank and bevel gear transmission for converting rotary movement of said cam means into angular movement of said piston means about its axis. 

1. In a system for controlling compression ignition engines, piston means having a central axis and an exterior control surface inclined with respect to said axis, cylinder means housing said piston means and guiding the latter for movement along said axis thereof, said cylinder means forming a servocontrol with said piston means and said cylinder means being formed with an overflow bore extending through a wall of said cylinder means to be covered and uncovered by said piston means, said piston means being rotatable within said cylinder means as well as being axially movable therein, a manually operable speed control means, slide valve means communicating with said cylinder means for controlling the flow of pressure fluid into said Cylinder means at opposite sides of said piston means, centrifugal governor means coacting with said slide valve means for controlling the latter, linkage means coacting with said speed control means, governor means, and piston means for controlling said governor means and said piston means in response to actuation of said speed control means while freeing said piston means for rotary movement about its axis, and metering means operatively connected with said linkage means for metering the supply of fuel to the engine according to the axial position of said piston means in said cylinder means.
 2. The combination of claim 1 and wherein said piston means has circumferentially distributed about its axis four inclined control surfaces in the form of projections defining at the exterior of said piston means four chambers distributed circumferentially thereabout and forming one pair of opposed charging chambers and another pair of opposed discharge chambers, said piston means being formed with one pair of passages providing communication between said charging chambers and one side of said piston means and with a second pair of passages providing communication between said discharge chambers and the other side of said piston means, and said cylinder means being formed in a plane perpendicular to said piston axis with a pair of opposed charging bores communicating with chambers said charging chambers and with a pair of opposed overflow bores communicating with said discharge chambers.
 3. The combination of claim 2 and wherein said piston means is a differential piston means having at its opposite sides different effective areas the smaller of which is in constant communication with a distribution chamber of said slide valve means and the larger of which is placed in intermittent communication with said distribution chamber by the control of said slide valve means through said centrifugal governor means.
 4. The combination of claim 3 and wherein a fuel control means is operatively connected to said piston means for regulating the angular position thereof in said cylinder means.
 5. The combination of claim 1 and wherein a cam means is situated between said speed control means and linkage means for controlling said linkage means according to a predetermined program to provide predetermined fuel supplies at certain engine speed ranges.
 6. The combination of claim 5 and wherein said linkage means includes a bellcrank and bevel gear transmission for converting rotary movement of said cam means into angular movement of said piston means about its axis. 